Commonly known laminated film bags, to be duly filled and subsequently fastened to a manual pump, require an essentially cylindrical collar made of a rigid material, which is secured permanently (welded) to the said bag.
The welding zone between the laminated film sheets forming the bag and the collar is particularly critical and irregularities are often created in this zone, which allow air to enter the bag, thereby contaminating the product contained therein and compromising the seal of the bag/pump system.